1. Field of the Invention
The present invention relates to substrate processing, and more particularly to improving the substrate processing by using multi-pitch scatterometry targets for de-convolving lithographic process parameters during Single-Patterning (S-P) procedures, Double-Patterning (D-P) procedures, and Double-Exposure (D-E) procedures.
2. Description of the Related Art
Many multiple patterning techniques are currently being used during semiconductor substrate processing to increase the number of features and/or structures within devices on a substrate. Multiple patterning techniques can include double exposure techniques, double patterning techniques, spacer techniques, mask techniques, and brute force techniques. In 2006, the International Technology Roadmap for Semiconductors was expanded to include double patterning as a potential solution for 32 nm (nanometer) lithography. Multiple patterning techniques are viewed by some device manufacturers as bridge solutions that can be used until Extreme Ultra-Violet (EUV) techniques become more fully developed.
As substrate geometries continue to shrink, the process window shrinks as well. The need to tightly control and understand critical dimension (CD) variations becomes more and more critical. Typically, APC control uses exposure dose alone as a single control knob for CD variation. In reality, there are other process parameters that are affecting CD, and the other process parameters can include focus and post exposure bake (PEB) temperature. Conventional metrology targets and techniques do not provide the necessary parameter sensitivity required to detect and differentiate the variation due to focus, dose, and PEB temperature